Mismatches between the rate of product input to and output from a conveyor are typically taken care of with some sort of diverting, delay, or storing action. For example, a temporary oversupply of product is often accommodated by simply loading excess product on trays manually and manually reintroducing them later when the situation is corrected. Aside from being a rather haphazard, unorganized approach, this also requires careful replacing of items which require a particular orientation for processing. Another approach uses spiral or other sorts of delaying conveyors which are permanently a part of the system for use, for example, in increasing transit time of product in a freezing or heating compartment.